A substance deposited on the sides of wine casks, during the time that the wine is in a state of fermentation. This substance being scraped off, and in its natural and unpurified state, is called by chemists super-tartrate of potash, and popularly, crude tartar. Tartar is distinguished, from its colour, into red and white, according to the colour of the wine from which it originates. All wines do not afford the same proportion of tartar; according to Dr. Newmann, the wines of Hungary yield but little tartar, those of France somewhat more, while the Rhenish wines afford the purest tartar in large quantities. The method adopted at Montpelier, according to Dr. Ure, for purifying this substance from an abundance of extractive principle, is as follows. "The tartar is dissolved in water, and suffered to crystallize by cooling; the crystals are then boiled in another vessel, with the addition of five or six pounds of the white argillaceous earth of Murviel to each quintal of the salt. After this boiling of the earth, a very white salt is obtained by evaporation, which is known by the name of cream of tartar, or the acidulous tartrate of potash," or purified super-tartrate of potash.
Emetic tartar is the tartrate of potash, and antimony. Regenerated tartar, the acetate of potash. Salt of tartar, the subcarbonate of potash. Soluble tartar, the neutral tartrate of potash. Vitriolated tartar, sulphate of potash.